It looks like support has not been implemented in GCC. Vice versa, you cannot have a lambda inside a pack expansion (to produce one lambda per pack argument). It seems the two features don't play together at all.
If you simply use [&]
instead, then there is a more helpful error message:
sorry, unimplemented: use of ‘type_pack_expansion’ in template
Disclaimer: My copy of GCC was built in late July; I'm probably due for an upgrade.